The invention relates to grommet-type joints for electrical connectors, and to electrical connectors which are sealed by means of such joints.
Grommet-type joints commonly used in the art are integrally made of an elastomeric material. They are arranged in dedicated rear skirts of connector housings and eventually held in place by a grid, which bears on the grommet rear side and which is releasably fastenable to the housing.
More specifically, the invention relates to grommets comprising
a peripheral portion having a peripheral outer surface provided to sealingly engage a peripheral inner surface of a connector housing, and
a central portion having at least one through passage for a wire, said passage extending in an axial direction.
In the connector assembling process, the terminals are inserted through the grommet passages in respective chambers provided in the insulating housing.
In conventional grommets, the central portion is continuously formed with the peripheral portion and/or attached to the peripheral portion at its corners. When the grommet is outwards restrained by the housing at the peripheral portion, the central portion can only expand by radial compression of the elastomeric material upon insertion of the terminals.
Said compression deformability is low, whereby the insertion force to be applied to the terminals and cable is relatively high.
In addition, the low deformability of the grommet passages makes it difficult to use the same grommet for different cable diameters with a high sealing efficiency.
Moreover, because of damage caused by the high insertion force between terminal and grommet, the sealing efficiency of such a grommet highly decreases after several insertion/withdrawal operations.